Recently, semiconductors are significantly used as an inevitable part in not only an electron industry but also various industrial fields. For example, a typical semiconductor chip is produced by slicing a silicon single crystal into a given thickness to form a silicon wafer and then forming a plurality of integrated circuits and the like on the silicon wafer.
In the production steps of the semiconductor chip, the silicon wafer placed on an electrostatic chuck is subjected to various treatments such as etching, CVD and the like to form conductor circuits or the like, or a resin for the resist is applied and dried by heating. In such treatments is frequently used a ceramic heater. For instance, ceramic heaters using a carbide or a nitride as a starting material are disclosed in JP-A-11-40330, JP-A-4-300249 and the like. However, these techniques have a problem that temperature distribution between heating elements is apt to become ununiform. In this connection, JP-A-11-251040 proposes a technique that the scattering of the thickness in the resistance heating body embedded in the inside of the substrate is made small for uniformizing the temperature distribution in the heating face of the ceramic heater. In this technique, however, since the heating body is embedded in the inside of the substrate, a distance of the heating body to the heating face of the substrate is too small, so that the technique is still insufficient in a point of ensuring the uniform temperature distribution over the whole face of the substrate.